2. Taxonomy
Taxonomy – field of classifying organisms & assigning each organism a universally accepted name
Binomial nomenclature –
2-word naming system by Carolus Linnaeus
Always in italics, first word is capitalized, second word is lowercased.
Genus species
Example:
Homo sapien (human)
Ursus arctos
Ursus maritimus

3. Taxonomy
All life is classified into 3 domains based on common characteristics:
Eubacteria: prokaryotes; “true” bacteria; Ex. Pathogens
Archaebacteria: prokaryotes; live in extreme environments
Eukarya: eukaryotes; Ex. plants, animals, fungi, protists

4. Taxonomy
Each domain can be broken down into more and more specific levels based on shared characteristics:
Kingdom
Phylum
Class
Order
Family
Genus
Species
Thus in binomial nomenclature, we name organisms based on their two most specific names
Pause and Play: Great Crash Course video if you want to pause in notes here and show it:

5. Evolutionary History
Phylogeny - evolutionary history of a species or a group of related species.
Phylogenetic Tree – diagram that biologists use to predict the evolutionary relationships of organisms
Organized based on evidence as well as taxonomy
Constructed to make the simplest relationships possible

6. Phylogenetic Trees
Classifies organisms into major taxa (groups) based on evolutionary relationships.
Classifies species in the order in which they descended from a common ancestor using physical characteristics.
Trees can show order of species divergence from the common ancestor and some even more specifically show time of divergence.

7. Phylogenetic Trees From a phylogenetic tree we can learn:
Which groups are most closely related
Which groups are least closely related
Which group diverged first (longest ago)

8. How to Read them Speciation - branching of a family tree
Extinction - loss of one of the branches.
Start from the “trunk” – this always represents a common ancestor that all organisms on the tree evolved from
Each node represents a more recent common ancestor

9. How NOT to Read them They do not show that A  B  C  D
Ex. Bacteria  Amoeba  Insect  Trout  Human and Bird is NOT correct
They do not show A > B > C > D
Ex. Humans are not greater than trout which is not greater than insects….etc.

10. Example What do you know from this phylogenetic tree?